Method for manufacturing battery external terminal

Abstract

To provide a manufacturing method of an external terminal for a battery to which a bus bar is easily welded.SOLUTION: An undercut part 13a is formed by outwardly flattening the outer periphery of the end face of a projecting part of a joining member by pressurizing both members in the compressing direction in a state of fitting a recessed part 21 of a metallic joined member 20 to the projecting part 13 of the metallic joining member 10. In the method of manufacturing the battery outer terminal 1 formed by integrally joining both members, a pressing die 4 for compressing a member to be joined from above has a projecting 4a on its pressing face, and a recessed part 22 to be a mark when welding a bus bar is formed by the projecting part on the face of the member to be joined compressed by the pressing die.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an external battery terminal used on the negative electrode side of a secondary battery, and a method for manufacturing the same. [Background technology]

[0002] A known negative electrode external terminal for a lithium-ion secondary battery is shown in Patent Document 1. This negative electrode external terminal is formed by joining a copper member and an aluminum member, with a current collector extending from inside the battery connected to the aluminum member, and a bus bar welded to the surface of the copper member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-176285 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional negative electrode external terminals, there is no mark to serve as a guide when welding the bus bar to the copper member, making alignment difficult whether welding is automatic or manual.

[0005] The present invention has been made to solve the above problems, and has an object to provide a method for manufacturing a battery external terminal that makes it easy to weld a bus bar. [Means for solving the problem]

[0006] The above-mentioned problem can be solved by a method for manufacturing an external terminal for a battery, in which the convex portion of a metal joining member is fitted into the concave portion of a metal joinee member and pressure is applied in a direction compressing both members, thereby flattening the outer periphery of the end face of the convex portion of the joining member outward to form an undercut portion, and joining the two members together, in which the stamping die that compresses the joinee member from above has protrusions on its pressing surface, and the protrusions form concave portions on the surface of the joinee member compressed by this stamping die. [Effects of the Invention]

[0007] According to the present invention as described above, a recessed portion that serves as a marker is formed on the surface of the joined member, so that a method for manufacturing a battery external terminal that makes it easy to weld a bus bar can be provided. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing a state before joining of an external terminal for a battery manufactured according to the present invention. [Figure 2] 1A to 1C are diagrams illustrating a joining process for a battery external terminal manufactured according to the present invention. [Figure 3] 1 is a front cross-sectional view of an external battery terminal manufactured according to the present invention. [Figure 4] 1 is a plan view of an external terminal for a battery manufactured according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a method for manufacturing an external terminal for a battery according to the present invention will be described with reference to the drawings.

[0010] As shown in FIG. 1, in the manufacturing method of an external terminal for a battery, a joining member 10 made of a copper material having a shaft portion 11, a flange portion 12, and a protrusion 13, a member to be joined 20 made of a columnar aluminum alloy material having a recess 21 formed therein that fits into the protrusion 113 while abutting against the flange portion 12, and a receiving die 3 and a pressing die 4 arranged so that these two members can be pressed together are used, and the member to be joined 20 is integrally joined to the joining member 10 by applying pressure with the pressing die 4, thereby manufacturing an external terminal for a battery on the negative electrode side.

[0011] The receiving die 3 has an expanded hole 3a that guides a part of the workpiece 20, and a positioning hole 3b that communicates with the expanded hole 3a and positions the shaft 11 of the joining member 10. A knockout pin 5 that extends concentrically with the positioning hole 3b is arranged so as to be able to protrude, and the end face of the knockout pin 5 is configured to close the bottom of the positioning hole 3b.

[0012] In addition, the knockout pin 5 is configured to position the flange portion 12 of the joining member 10 in the positioning hole 3b in the expanded hole 3a of the receiving die 3, and to expose the convex portion 13 of the joining member 10 from the receiving die 3.

[0013] Furthermore, when the knockout pin 5 protrudes into the positioning hole 3b after the pressing die 4 is retracted, the shaft portion 11 of the joining member 10 located in the positioning hole 3b is removed from the receiving die 3 together with the joined member 20 to which it is integrally joined.

[0014] As shown in FIG. 2, the press die 4 is configured to work-harden the low-hardness to-be-joined members 20 during molding, thereby increasing their hardness and pressing the protrusions 13 of the joining members 10, which have a high hardness, through the inner walls of the recesses 21.

[0015] The joining member 10 undergoes plastic deformation such that the upper end surfaces of its protrusions 13 extend in a direction intersecting the pressure direction, while the outer periphery of its upper end flattens outward to form an undercut portion 13a. Accordingly, the joined member 20 also undergoes plastic deformation, causing its excess material to wrap around the back surface 11 of the undercut portion 13a, and the joined member 20 is tightly attached to the entire surface of the undercut portion 13a. In this way, the joining member 10 and the joined member 20 are mechanically joined, thereby producing the negative-side external battery terminal 1 for a secondary battery shown in FIGS. 3 and 4.

[0016] The press die 4 has a protrusion 4a at the center of the surface that presses the workpiece 20, and the protrusion 4a forms a recess 22 on the surface of the workpiece 20 that is compressed by the press die 4.

[0017] According to the manufacturing method for a battery external terminal described above, the recessed portion 22 is formed in the process of manufacturing the battery external terminal 1 by joining dissimilar metals together. This recessed portion 22 serves as a mark when welding a bus bar to the surface of the battery external terminal 1. In other words, according to the manufacturing method for a battery external terminal of the present invention, a mark can be easily provided on the battery external terminal 1 formed by joining dissimilar metals together.

[0018] The specific configuration of each part of the present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the spirit of the present invention. For example, although the joining member 10 is made of a copper material, it may also be made of a metal material with higher hardness, such as an iron material. [Explanation of symbols]

[0019] 1 External terminal for battery 3. Receiving type 3a Expanded hole 3b Positioning hole 4 Press mold 4a Protrusion 10 Joint material 11 Shaft 12 Collar 13 Convex part 13a Undercut section 20 Parts to be joined 21 Recess 22 Recessed part

Claims

[Claim 1] A method for manufacturing an external terminal for a battery, comprising the steps of: fitting a convex portion of a metal joining member into a concave portion of a metal joined member; and compressing both members in a compressive direction, thereby flattening the outer periphery of the end face of the convex portion of the joining member outward to form an undercut portion, thereby integrally joining the two members; A method for manufacturing an external terminal for a battery, characterized in that a pressing die that compresses the joined members from above has protrusions on its pressing surface, and the protrusions form recesses on the surface of the joined members compressed by this pressing die.

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